Polaroid (POL) is an essential part of a Liquid Crystal Display (hereinafter referred to as LCD) for realizing a display function. In a manufacturing process of the LCD, POL is necessarily attached to a display panel by using a film attaching device.
FIG. 1 is a schematic diagram showing a film attaching device in the prior art. As shown in FIG. 1, the film attaching device generally includes a platform, and a first roller 2 and a second roller 3 which are disposed in parallel on both sides of a carrying surface of the platform. The rollers are used to laminate a POL onto a display panel when the display panel and POL placed on the platform pass between the first roller 2 and the second roller 3. In general, only one roller (for example, the second roller 3 located at the upper portion in FIG. 1) can be observed by an operator.
When the film attaching device attaches the POL to the display panel, projections of the first roller 2 and the second roller 3 on the carrying surface of the platform are required to completely coincide, otherwise linear bubbles may occur on the display panel or the display panel may jitter, thereby leading to spots (Mura) on the display screen. However, the operator generally cannot observe the lower first roller 2, which causes that it is difficult to regulate the first roller 2 and the second roller 3 to coincide.